Heretofore, the amount of magnetic material such as ferrite generally incorporated into a composition has been limited by the type of binder utilized For example, Leguillon U.S. Pat. No. 3,124,725 relates to a flexible plastic permanent magnet having a body portion and a relatively thin elastic high skin strength cover which is highly resistant to cracking so that the plastic permanent magnet as a whole is highly resistant to cracking in service.
Manuel et al U.S. Pat. No. 3,282,909 relates to metal carbonyl polymer complexes which can be blended with conventional synthetic rubbers and heattreated or vulcanized in the presence of a strong magnetic field thereby enhancing the magnetic properties of the resulting polymer
Doser et al U.S. Pat. No. 3,933,536 relates to magnets which are produced by dissolving an organic polymer in a solvent, adding a magnetic powder to the solution, and then adding the solution to a vehicle in which the polymer is insoluble.
Deschamps et al U.S. Pat. No. 3,956,440 relates to the production of fine grained ferrite bodies utilizing a process for the production of ferrimagnetic materials obtained by coprecipitation from a stoichiometric mixture of metallic salts corresponding to the material composition by means of a base comprising an isostatic pressing step of the dried oxides followed by a short vacuum heat treatment of complete duration under 12 hours.
Baermann U.S. Pat. No. 4,190,548 relates to a plastic bonded permanent magnet having magnet particles which have a high affinity for oxygen such as ultra-fine grain iron, bismuth-manganese and cobalt rare earth magnetic materials, dispersed within a substantially oxygen-free plastic.
Beck U.S. Pat. No. 4,200,547 relates to a matrix-bonded permanent magnet comprising anisotropic magnetic particles which have an alignment exceeding 90 percent. The binder is a mixture of an amorphous hot-melt polyamide resin and a processing additive which is a cyclic nitrile derivative of a saturated fatty acid dimer.
Kotani et al U.S. Pat. No. 4,292,261 relates to a pressure sensitive conductor and method of manufacturing the same wherein the conductor comprises an elastomer containing from 3 to 40 percent by volume of conductive magnetic particles.
Loubler U.S. Pat. No. 4,496,303 relates to a method of fabricating a permanent magnet wherein a plastic bonded magnet is formed of a solidified mixture of a thermoplastic powder and magnetic particles capable of being permanently magnetized.
Yamashita, et al U.S. Pat. No. 4,689,163 relates to a resin-bonded magnet comprising particles of a melt-quenched ferromagnetic material and a binder having at least an alcoholic hydroxyl group and a block isocyanate with an active hydrogen-bearing compound.